---
title: "Elementary Data Tests"
sidebarTitle: "Introduction"
---

Elementary provides tests for detection of data quality issues.
Elementary data tests are configured and executed like native tests in your dbt project.

Elementary tests can be used in addition to dbt tests, packages tests (such as dbt-expectations), and custom tests.
All of these test results will be presented in the Elementary UI and alerts.

<Snippet file="data-tests/tests-cards.mdx" />

## Anomaly detection tests

Tests to detect anomalies in data quality metrics such as volume, freshness, null rates, and anomalies in specific dimensions.

<Tooltip tip="Anomaly detection test result example from Elementary report">
  <img src="/pics/anomalies/anomaly-example.png" alt="Demo" />
</Tooltip>

<Tip>
  [How Elementary anomaly detection tests
  work?](/data-tests/how-anomaly-detection-works)
</Tip>

<Card
  title="Volume anomalies"
  href="/data-tests/anomaly-detection-tests/volume-anomalies"
>
  Monitors table row count over time to detect drops or spikes in volume.
</Card>
<Card
  title="Freshness anomalies"
  href="/data-tests/anomaly-detection-tests/freshness-anomalies"
>
  Monitors the latest timestamp of a table to detect data delays.
</Card>

<Card
  title="Event freshness anomalies"
  href="/data-tests/anomaly-detection-tests/event-freshness-anomalies"
>
  Monitors the gap between the latest event timestamp and its loading time, to
  detect event freshness issues.
</Card>

<Card
  title="Dimension anomalies"
  href="/data-tests/anomaly-detection-tests/dimension-anomalies"
>
  Monitors the row count per dimension over time, and alerts on unexpected
  changes in the distribution. It is best to configure it on low-cardinality
  fields.
</Card>

<Card
  title="Column anomalies"
  href="/data-tests/anomaly-detection-tests/column-anomalies"
>
  Monitors a column for anomalies in metrics such as null rate, length, max and
  min, and more. Read more about [specific column
  metrics](/data-tests/anomaly-detection-configuration/column-anomalies).
</Card>

<Card
  title="All columns anomalies"
  href="/data-tests/anomaly-detection-tests/all-columns-anomalies"
>
  Activates the column anomalies test on all the columns of the table. It's
  possible to exclude specific columns.
</Card>

## Schema tests

<Card title="Schema changes" href="/data-tests/schema-tests/schema-changes">
  Fails on changes in schema: deleted or added columns, or change of data type
  of a column.
</Card>

<Card
  title="Schema changes from baseline"
  href="/data-tests/schema-tests/schema-changes-from-baseline"
>
  Fails if the table schema is different in columns names or column types than a
  configured baseline (can be generated with a macro).
</Card>

<Card title="JSON schema" href="/data-tests/schema-tests/json-schema">
  Monitors a JSON type column and fails if there are JSON events that don't
  match a configured JSON schema (can be generated with a macro).
</Card>

<Card title="Exposure schema" href="/data-tests/schema-tests/exposure-tests">
  Monitors changes in your models' columns that break schema for downstream
  exposures, such as BI dashboards.
</Card>

## Other tests

<Card title="Python tests" href="/data-tests/python-tests">
  Write your own custom tests using Python scripts.
</Card>
